Heat exchangers are used to transfer thermal energy between two (or more) fluids while maintaining isolation between the fluids. Such devices typically operate by providing discrete channels or fluid flow paths for each of the fluids. Thermal energy from the hotter of the fluids is convectively transferred to the channels or flow paths through which that fluid is directed, is transferred (typically by thermal conduction) to the channels of flow paths through which the cooler of the fluids is directed, and is convectively transferred to that fluid.
Certain challenges are known to result when one of the fluids is at an elevated pressure. The elevated fluid pressure acting on the walls of channels through which the pressurized fluid is directed frequently mandates the use of channels that are rather small in size, in order to maintain acceptably low levels of mechanical stress. However, such small channel sizes also reduce the amount of surface area available to achieve the desired heat transfer, leading to increases in the length and/or number of such channels in order to meet the performance demands. Such increases lead to increased cost, size, and manufacturing complexity, and can be especially challenging in application where compact heat exchangers are desirable. Such applications, by way of example only, include refrigeration systems, fuel heating for combustion engines, vaporizers for fuel cell systems, Rankine cycle waste heat recovery evaporators, and others.